The present invention relates to .alpha.-olefin copolymers containing pendant hindered amine groups which are useful as light and heat stabilizers for organic materials and to stabilized compositions containing said copolymers.
The hindered amine compounds having the 2,2,6,6-tetra-substituted piperidinyl structure have long been known as effective light stabilizers for organic materials and have enjoyed considerable commercial success.
Such hindered amine light stabilizers are described in detail by H. J. Heller and H. R. Blattmann, Pure and Applied Chemistry, 36, 141-161 (1973).
It is known from U.S. Pat. No. 3,705,166 that monomeric acrylic acid derivatives which contain at least one piperidinyl group having a sterically hindered nitrogen atom may be used as light stabilizers in organic polymers. However, these acrylic acid derivatives tend to be too volatile.
In U.S. Pat. Nos. 4,210,612 and 4,294,949 homopolymeric and certain copolymeric compounds having pendant hindered amine moieties are described as useful light stabilizers. The homopolymers are those made by the free radical polymerization of acryloyl or methacryloyl derivatives of compounds containing hindered amine moieties. The copolymers are those made by the free radical copolymerization of the acryloyl or methacryloyl substituted hindered amine monomers with other ethylenically unsaturated monomers such as styrene, an alkyl acrylate, an alkyl methacrylate, acrylonitrile, a maleimide or N-vinylpyrrolidone. Although .alpha.-olefins are generically disclosed as possible comonomers among a very wide variety of ethylenically unsaturated monomers, ethylene copolymers containing pendant hindered amine moieties are not described nor are their particularly advantageous properties contemplated.
Copolymers of acryloyl or methacryloyl substituted hindered amine monomers with acryloyl or methacryloyl monomers containing light absorbing moieties such as the benzophenones, benzotriazoles, .alpha.-cyanocinnamates or benzalmalonates are described in U.S. Pat. No. 4,276,401 as being useful light stabilizers for organic materials.